Recreate BI's Edge in compositor?
This probably isn't the answer you are looking for, but you could always render out using BI at the end of production, with a 'shadeless' white material applied in the render-layer settings as the material override (applies to all objects when rendered) Also, set the world colour as 100% white as well.



render result



This would then allow you to composite the rendered image or sequence of images ontop of your cycles render, you can use a colour mix -> multiply so that only the black 'edge' is applied to the cycles render.